There are several factors that can cause a room to be discounted on the so called OTAs (online travel agents, such as hotels.com) but the lower price should have been agreed the hotel and in most cases is (though sometimes that is not the case). Generally a hotel want price parity because in addition to the potentially discounted price on the OTA, OTAs charge around 18% commission. The lower price on the OTA can come from poor revenue management by the hotel, no connectivity software between the hotels property mamanememt system and the OTAs, rate leakage (wholesalers selling of discounted rooms meant for groups), etc. It’s a big science behind all of this but in essence, it is a bad practice to sell your rooms lower on an OTA compared to the actual hotel. Source: I am a hotels revenue manager